This invention relates to editing apparatus which controls the transfer of signals from a playback medium to a recording medium and, more particularly, to improved data display features in such apparatus.
In the general field of data recording, it often is desirable to create a finalized recording derived from portions Of pre-existing recordings and other sources of data. It also is desirable to modify one recording by selectively inserting thereinto various bits and pieces which are derived from other recordings. Such creations and modifications of recordings are referred to generally herein as "editing".
While editing is used generally in most fields of data recording, it has become a highly specialized and advantageous technique in the field of video recording. Thus, video signals which are recorded on a particular record medium, such as a magnetic tape, a magnetic disk, or the like, are "edited" by selectively assembling or inserting other video signals onto that record medium. For the purpose of the present discussion, the record medium on which the video signals are recorded is described as magnetic tape which, presently, is the most common form of record medium that now is used for recording video programs. Typically, in the field of broadcast and commercial video tape recording, video signals which are recorded on one tape are reproduced by a video tape recorder (VTR) for an "insert" or "assemble" recording by another VTR on recording tape. As is known to those of ordinary skill in the art of video editing apparatus, an "insert" edit operation describes the insertion of video signals into a predetermined location on a video tape, the "inserted" signals being preceded and followed by pre-existing video signals. In an "assemble" mode of operation, video signals are recorded in following relation (i.e. assembled) to pre-existing information.
As is recognized, to carry out the insert and assemble edit modes of operation, it is necessary for an operator to select appropriate portions, or blocks, of video signals which are to be reproduced from one tape (referred to generally as the source or playback tape) and which are to be recorded at other locations on the recording (or destination) tape. That is, the operator must be aware of the particular addresses on the source tape at which desired video signals are recorded as well as addresses on the destination tape at which new video signals are to be placed. These "addresses" on the respective video tapes generally are recorded as time code addresses, each of which separately identifies a respective frame of the recorded video signal. An example of one type of time code address which is used with, for example, the recording of NTSC signals is the so-called SMPTE (Society of Motion Picture and Television Engineers) time code which represents frame addresses in terms of hours, minutes, seconds and frames up to a maximum value of 23 hours, 59 minutes, 59 seconds and 29 frames. Although other acceptable time code addresses are known, for convenience, and in the interest of simplification, the present discussion refers only to this SMPTE time code.
It is conventional to record the time code longitudinally, that is, in serial tracks along a length of the video tape. Time code generators and readers are known for the recording and reading of such time codes as the video tape is transported. These time codes, as read from the video tape, are used to designate so-called "edit-in" and "edit-out" locations of the respective playback and recording tapes.
To carry out an edit operation, the time code addresses which identify the particular frames on the playback tape which define the video information that is to be re-recorded on the recording tape are marked, or stored, as the edit-in and edit-out points. For an insert edit mode, the desired edit-in and edit-out points on the recording tape likewise are marked, or stored. Of course, for favorable results, that portion of the playback tape which subsists between the edit-in and edit-out points should be equal to the corresponding portion on the recording tape. Once the operator confirms that the material, or video signals, lying between the edit-in and edit-out points on the playback tape is correct and should be re-recorded between the edit-in and edit-out points on the recording tape, the actual transfer of video signals may occur. Such confirmation of this edit operation is known as a "preview", and the previewed operation may be monitored on a suitable video display monitor device. If changes are to be effected to the respective edit-in and edit-out points, for example, if the operator finds other material which he wishes to transfer from the playback tape to the recording tape, or material which should be deleted from the recording tape, the time code addresses which define the respective edit points may be suitably changed.
In an assemble edit mode of operation, it may not be necessary to define an edit-out point for the recording tape. This is because, in the assemble edit mode, the selected video signals which are reproduced from the playback tape, and which lie between the edit-in and edit-out points thereon, merely are added to (i.e. assembled) the previously-recorded video signals on the recording tape commencing from the edit-in and edit-out point thereon.
In many types of VTR edit apparatus presently available, respective edit-in and edit-out points for the playback and recording tapes can be stored merely by operating suitable selector switches when the respective tapes arrive at their desired time code addressed locations. However, the edit-in and edit-out points for each tape often are not displayed. This makes it difficult for the operator to effect relatively small, or fine, adjustments to these respective points. Also, the operator is deprived of important information which, advantageously, would assist him in carrying out an edit operation.
Another disadvantage of VTR edit apparatus which presently is available is the difficulty in transferring time code addresses for effecting modifications in the various edit points that have been selected. For example, let it be assumed that the operator has selected one particular edit-in point for the playback tape. Upon reviewing this tape, he may determine that, possibly, another edit-in point should be selected. In the aforementioned presently available VTR edit apparatus, only one of these edit-in points can be selected and stored. Consequently, the operator must undertake a rather laborious and time-consuming task to compare the two edit-in points which he has selected in order to determine which of these points ultimately should be used. There is, therefore, a need to store two or more time code addresses from which the operator easily can choose which one is to be used in the actual edit operation. In conjunction with this need is a need to permit easy transfer of such stored time code addresses, preferably by simple pushbutton operation.
As will be described hereinbelow, in the apparatus disclosed herein, which is similar to the apparatus disclosed in copending application Ser. No. 139,444 filed Apr. 11, 1980, an edit operation can be carried out if only three of the four edit points (that is, the edit-in points for each of the playback and recording tapes as well as the edit-out points for each tape) are known. This is because, in carrying out the edit operation, the tapes are driven in synchronism, and an edit point for one also serves as a corresponding edit point for the other. Nevertheless, for automatic edit operation, both the edit-in and edit-out points for one tape should be specified, as well as one of the edit-in and edit-out points for the other tape.
Although an edit operation can be carried out when only three of the four edit points are known, an operator often finds it desirable to verify the remaining edit point. For example, in establishing the parameters for the edit operation, the operator may designate specific edit-in and edit-out points for the playback tape, and may also designate a specific edit-in point for the recording tape. This could occur if the operator is aware of a specific segment on the playback tape which he wishes to transfer to the recording tape, and he also knows the particular location on the recording tape at which this segment should begin. However, he might not be fully cognizant of the information which would remain on the recording tape following this insertion. To best preview his proposed edit, the corresponding edit-out point which will result for the recording tape should be specified. Presently available editing devices do not indicate the time code address for such a resultant edit-out point without requiring the operator to undertake a time-consuming and complex data manipulation operation.
Furthermore, in selecting the parameters for an edit operation, the operator may select intermediate edit-in or edit-out points along one tape, such as when setting up a so-called agenda-edit operation (described in copending application Ser. No. 139,448 filed Apr. 11, 1980, for controlling the transfer of signals on the other tape. For example, an intermediate edit-in point along the playback tape may be designated, whereby when the playback tape reaches that intermediate edit-in point, signals will be transferred to the recording tape. Additional intermediate edit points also may be established for the recording tape. If one such intermediate edit-in point is indicated by the time code address of the playback tape and another intermediate edit-in point is designated by the time code address of the recording tape, the operator might not readily recognize which of these intermediate points will be reached first. Therefore, there is a need to permit conversion of the time code address representing an intermediate edit point along one tape to the time code address representing the corresponding edit point along the other tape.